instead of using a stroke, just draw a square with no stroke with a grey fill, and then a white square with no stroke drawn over the grey square. the thick lines just have curved ends.
:thumb: no problem. I find it helpful to use the coordinates and the height and width values in the properties panel to make sure everything is being done exact. like if you just draw a random square you can say x:0 y:0 height:40 width:40, then make another square and say x:10 y:10 height:20 width:20 to get a nice 20x20 box with a border of 10, or you could just hit ctrl+k for the align and do them in a movie clip and center them. ::shrug::